1. Field of the Invention
The present invention relates to the production of suitable mixtures which, after roasting, can produce a coke suitable for use in a shaft furnace, and more particularly, to a carbonaceous material which can be mixed with "basic coal" so as to obtain such suitable mixtures.
2. DESCRIPTION OF THE PRIOR ART
As a result of recent developments in the iron and steel industry, the amount of coke needed in this industry for producing the intended products has increased whereas the amount of available high quality coal which is needed to produce such coke is limited and is becoming increasingly difficult to obtain.
The coke used in shaft furnaces usually is in the form of a block coke of more than 25 mm in dimension, and since a powdered coke with smaller dimensions is inert, such a product is not a useful raw material, i.e., for use in a shaft furnace process. Such a powdered coke finds use generally only as a raw material for sintered ores. A method of use of such a powdered coke in making cokes useful in a shaft furnace would be certainly most desirable.
At the same time, much research has been recently directed towards the successful gasification of coals; however, it is so difficult to gasify coal that in most cases a char residue is produced (the char being obtained by heating noncaking coal). This char is inert and therefore is not generally useful except as a fuel. In effect, research into the gasification of coal has been somewhat hampered by the problems associated with utilization of the char by-product.
With regard to the foregoing inert powdered cokes and coal gasification chars, such materials cannot be successfully utilized as raw materials for producing shaft furnace cokes largely because (a) such materials have no meltability and will not react with the molten components in the basic coals with which they are mixed, and (b) such materials are porous and are therefore not effectively coated with the molten components in the coal with which they are mixed. Even if such materials are used, e.g., in admixture with basic coals to form a mixture suitable for roasting into a shaft furnace coke, they can only by used to a very small degree of the total mixture. At the same time, even a small amount has been found to decrease the ultimate coke strength (a very serious drawback).